Research On The Braking Energy Management And Control Strategy Of The Front-Mounted Parallel Hydraulic Hybrid Crane

As the rapid growth of the world economy,industrial production and transportation keep making progress.While with the oil resources getting scarce and the environmental pollution becoming increasingly aggravating,more and more attention has been paid to energy conservation and emission reduction worldwide.As a high energy consumption industry,the technical exploration related engineering machinery has never stopped,on the contrary,the voice is stronger in recent years.Among them,the hybrid technology is currently one of the effective ways to realize vehicle energy conservation and emissions reduction,the successful application of hybrid technology in the field of car provides a useful reference for energy saving and emission reduction for engineering machinery.In recent years,the study of hybrid construction machinery has been carried out at home and abroad,however,a large proportion of hybrid construction machinery focused on excavator,forklift trucks,bulldozers etc..Moreover,China’s research on hybrid construction machinery is relatively late,and there still is a certain gap between foreign countries and our country for the core technology.The autocrane is one of the most important machines in the field of construction machinery,it has great features that installed power,heavy load,frequent start and braking,large consumption and poor emission.There are very few kinds of hybrid crane products,the relevant theories are not perfect,the research of system integrity is lacking,and it is limited to the mode of hybrid electric vehicle,and there is no hydraulic hybrid product.While,as the high power density of hydraulic hybrid power system,it can also provide a large driving force while improving the fuel economy of crane,especially in the field of construction machinery with heavy load.In order to improve the truck crane machine performance,the industrial added value and core competitiveness,and promote technology innovation of the whole construction machinery industry and industry upgrading,carrying out the research of the truck crane hydraulic hybrid has important theoretical and practical significance.This thesis is a cooperation project between jilin university and a famous enterprise in China---“The Exploitation of Hydraulic Hybrid System for Crane Chassis”,taking the 50 t truck crane chassis as the research object,on the basis of theory research related the hydraulic hybrid system,through the parameter optimization matching of the key components of the system,designing reasonable control strategy,computer simulation and experiment,the detailed and in-depth research has been carried on for parallel hydraulic hybrid system to realize the targets of energy conservation and emissions reduction for the crane,which is very important both in theory and in reality.The paper mainly achieved the following aspects:1.On the base of full analysis about the research status of hybrid vehicles at home and abroad and the key technology of hybrid system,the front twin-shaft parallel hydraulic hybrid structure is put forward,which maks full use of the regulation of transmission,improves crane power performance significantly,and can meet the demand for vehicle refitting;2.The mathematical models of the vehicle longitudinal dynamics,engine,hydraulic pump/motor,the hydraulic accumulator and other key components are established from the perspective of system,which lays a theoretical foundation for system parameter matching and system simulation;3.Based on the analysis of the important parameters matching of the key components of truck crane hydraulic hybrid system,combining with the optimization objective function of the hybrid power system,the optimized matching for main parameters of key components of the system is done thorough the proposed improved multi-objective particle swarm optimization(IMOPSO),and the result of parameter optimization will be an important reference for the final selection of key components;4.Through the analysis of the whole machine driving mode,the control strategies of the braking energy regeneration and use,recharging initiatively are made.and in order to improve the perturbation robustness for the torque control in a wide range of system parameter,the fractional order PID is used to control the torque of hydraulic pump/motor,which is superior to the effect of the intelligent PID control;5.In order to shorten the development time and cost of hybrid system,looking for the best design scheme and design parameters,this paper uses the virtual prototype technology to set up front parallel hydraulic hybrid virtual prototype model of crane in the LMS Imagine.Lab AMESim multi-body dynamics simulation software,and the relevant simulation analysis and evaluation,find out the deficiency of the early plan,early forecasting performance of the system;.6.Based on a certain type of the domestic traditional crane,an experimental prototype of hydraulic hybrid crane is developed jointly with the enterprise,and the hydraulic hybrid system is successfully transplanted into the chassis of the crane.The performance test scheme of the system is designed and the physical prototype was tested.The correctness of theoretical analysis and simulation is verified.The research results of this paper has a certain reference value for the hydraulic hybrid dynamic simulation,optimization analysis,system performance evaluation,and so on,of engineering machinery.and has important theoretical significance and practical value.